The class of polymers of carbon monoxide and olefin(s) has been known for a number of years. Brubaker, U.S. Pat. No. 2,495,286 produced such polymers of relatively low carbon monoxide content in the presence of free radical catalysts, e.g., peroxy compounds. U.K. Pat. No. 1,081,304 produced similar polymers of increased carbon monoxide content in the presence of alkylphosphine complexes of palladium salts as catalyst. Nozaki extended this process through the use of arylphosphine complexes of palladium salts and certain inert solvents, e.g., U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, e.g., ethylene or ethylene and propylene, has become of greater interest because, in part, of the availability of such materials. The polymers have been shown to be of the formula --CO(A)-- where A is the moiety of ethylenically unsaturated hydrocarbon polymerized through the ethylenic unsaturation. For example, when the ethylenically unsaturated hydrocarbon is ethylene, the polymer will be represented by the formula --CO(CH.sub.2 --CH.sub.2). The general process for the production of these linear alternating polymers is illustrated by published Europeaun Patent Application Nos. 121,965 and 181,014. The process generally involves a catalyst composition formed from a Group VIII metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below 2 and a bidentate ligand of phosphorus, arsenic or antimony. The resulting polymers are relatively high molecular weight thermoplastic polymers having utility in the production of structural articles such as containers for food and drink and parts for the automobile industry.
The polyketones are characterized by relatively high melting points, generally over 175.degree. C., depending on the molecular weight and the chemical nature of the polymer. A melting point of this magnitude is of value in many applications, e.g., where a shaped article is to be subjected to conditions of elevated temperature. From a processing point of view, however, the high melting point is detrimental since additional energy is required to effect changes in the shape of a polymer article and sufficiently elevated temperatures cause some degree of thermal degradation.
The processing temperature of a polymer is often lowered through the production of a plasticized composition, that is, lowering a melting point through the formation of a composition comprising the polymer and a plasticizing agent. The resulting composition will have a melting point lower than the unplasticized polymer. However, once a plasticizing agent has been incorporated into a polymer, it is not generally possible to easily remove the plasticizing agent and return the polymer to the unplasticized state where the higher melting point is observed. It would be of advantage to produce plasticized compositions of polyketone polymers which exhibit greater processability at a comparatively lower temperature. It would also be of advantage to provide a composition which incorporates a plasticizer which, subsequent to processing, may be removed to regenerate the unplasticized composition.